Human TWEAK (UniProtKB O43508, TNF-related weak inducer of apoptosis; SEQ ID NO: 60) is a cell surface associated type II transmembrane protein. TWEAK is described in Chicheportiche, Y., et al., J. Biol. Chem. 272 (1997) 32401-32410; Marsters, S. A., et al., Curr. Biol. 8 (1998) 525-528; Lynch, C. N., et al., J. Biol. Chem. 274 (1999) 8455-8459. The active form of TWEAK is a soluble homotrimer. Human and murine TWEAK show 93% sequence identity in receptor binding domain. The TWEAK receptor Fn14 (fibroblast growth factor inducible 14 kDa protein) is a 129 amino acid type I transmembane protein consisting of one single cystein rich domain in ligand binding domain. Signaling of TWEAK occurs via NF-KB pathway activation. TWEAK mRNA is expressed in a variety of tissues and found in most major organs like heart, brain, skeletal muscle, and pancreas, tissues related to the immune system like spleen, lymph nodes, and thymus. Fn14 mRNA has been detected in heart, brain, lung, placenta, vascular endothelial cells (EC) and smooth muscle cells. TWEAK-null and Fn14-null knockout mice are viable, healthy and fertile and have more natural killer cells and display an enhanced innate inflammatory response. TWEAK is involved in apoptosis, proliferation, angiogenesis, ischemic penumbra, cerebral edema, and multiple sclerosis.
Anti-TWEAK antibodies are mentioned in WO 1998/005783, WO 2000/042073, WO 2003/086311, WO 2006/130429, WO 2006/130374, WO 2006/122187, WO 2006/089095, WO 2006/088890, WO 2006/052926.